The present invention relates generally to spring assemblies of the type formed with an array of coil springs, such as used in mattresses, furniture, and the like, and more particularly to a support spring for attachment to the perimeter of a mattress spring assembly to provide supplementary support thereat.
Bedding and like mattresses typically comprise a wire spring assembly encased within foam or fiber padding and an outer fabric covering. The spring assembly is normally formed of an array of coil springs arranged in longitudinal and transverse rows and border wires at the top and bottom of the spring array with the springs and border wires being integrated by a series of helical wires connecting the upper and lower coils of adjacent spring rows and also connecting the border wires to the upper and lower coils of the springs along the outer perimeter of the spring array. It is also common practice to provide a series of additional support springs between the border wires at spacings along the perimeter of the spring assembly to provide supplementary stiffness and support around the outer lateral edges or perimeter of the mattress, making the edges of the mattress stiffer and more comfortable for sitting.
Disadvantageously, the fabrication of a mattress spring assembly of the described type is labor intensive, particularly in the application of the helical connecting wires to connect the spring array to the border wires, causing many bedding assembly workers to experience Carpal Tunnel Syndrome and like cumulative trauma disorders to the musculature of the hands, wrists and lower arms. One acceptable alternative, which also may provide some improvement in the overall performance of the spring assembly, is to utilize discrete metal clips or bands, sometimes commonly referred to as "butterfly" clips at individual attachment locations between the perimeter springs and the border wires. The use of such clips, however, has met with resistance within the bedding industry because the helical wires have also been typically utilized to secure in place the perimeter support springs between the border wires of the spring assembly.
One attempt to address the problem of attaching mattress edge support springs when metal connector clips are used instead of a helical wire connector between the mattress border wires and the perimeter springs of the mattress, is disclosed in U.S. Pat. No. 5,062,171. This patent discloses an edge support spring fabricated entirely of a single strand of spring wire fashioned into a central torsion spring from which opposing springs arms extend outwardly, with the opposite ends of the spring arms being bent into the form of a U-shaped clip which may be snap-fit onto the border wires of a mattress spring assembly. One disadvantage of this edge support spring is the degree of bending required to form the clip portion at the opposite ends of each spring arm of each edge support spring, which necessitates a relatively complicated bending fixture.